For words that have only 3 letters, there is not any 4th letter. Such as with the word “include”, there aren't any extra letters afterwards and therefore need to be the word "include". The word “addict” is during the BIP39 wordlist however you would have made use of “addi” for https://agendabookmarks.com/story18772216/a-secret-weapon-for-bip39-words-to-numbers